Hydrothermally assisted bimetallic transition metal sulfide as battery grade electrode and activated carbon as capacitive electrode for hybrid energy storage devices

Hybrid energy storage systems grab intense attention owing to their versatile worth in energy applications. However, the enhancement of energy and power density still needs considerable attention. In this regard, we have stated the optimization of bimetallic sulfide synthesized via hydrothermal technique. Various samples of nickel manganese sulfide were prepared with varying concentration of each element in the binary composition. The structural and morphology analysis of the synthesized materials were accomplished through XRD, and SEM. The prepared binary metal sulfides were then electrochemically tested in three cell configuration which revealed that Ni0.50Mn0.50S hold the superior performance, recognizing it to be favorable for supercapattery application. A hybrid device NiMnS//Activated carbon was fabricated which delivered a decent energy and power density of 45.7 Wh/kg and 1700 W/kg, respectively, with an exceptional cycling stability of 81.1 % after 5000 cycles. Furthermore, to elucidate the hybrid nature of the fabricated device as well as to determine the capacitive and diffusive contribution, b-values and simulation of Dunn's model was employed. All of the impressive electro-chemical outcomes suggest Ni0.50Mn0.50S to be a potential contender for futuristic hybrid energy storage applications.